Presentation 15 - Musculoskeletal System

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Presentation 15 - Musculoskeletal System

  1. 1. The Musculo skeletal System Support, Protection, Movement and Locomotion
  2. 2. Skeletal Functions <ul><li>Framework for support </li></ul><ul><li>Transmits movement </li></ul><ul><li>Maintains shape </li></ul><ul><li>Protects internal organs from mechanical injury </li></ul><ul><li>Contains and protects the red bone marrow, one of the hemopoietic (blood-forming) tissues </li></ul><ul><li>Mineral reservoir - storage site for excess calcium and phosphorus </li></ul><ul><li>Storage of fats – yellow marrow </li></ul>
  3. 3. Cytoskeleton <ul><li>Maintains cell shape </li></ul><ul><ul><li>Microfilaments </li></ul></ul><ul><ul><li>Intermediate filaments </li></ul></ul><ul><ul><li>Microtubules </li></ul></ul><ul><li>Protection </li></ul><ul><li>Enables motion </li></ul><ul><ul><li>Cilia </li></ul></ul><ul><ul><li>Pseudopodia </li></ul></ul><ul><ul><li>Flagella </li></ul></ul><ul><li>Intracellular transport </li></ul><ul><li>Cell division </li></ul>
  4. 4. Structural support in plants <ul><li>Cell walls </li></ul><ul><li>Collenchyma and sclerenchyma tissue </li></ul><ul><li>Cellulose and lignin </li></ul>
  5. 5. Hydrostatic skeleton <ul><li>Fluid-filled closed chambers </li></ul><ul><li>Internal pressure generated by muscle contraction </li></ul><ul><li>e.g. sea anemone and worms </li></ul>
  6. 6. Exoskeleton <ul><li>Shelled molluscs (CaCO 3 ) </li></ul><ul><li>Arthropods (chitin) </li></ul><ul><li>Hard segments covering muscles and visceral organs </li></ul><ul><li>Muscles are attached to the exoskeleton </li></ul><ul><li>Restricts growth and size of insect  molting </li></ul>
  7. 7. Endoskeleton <ul><li>Endoskeleton </li></ul><ul><ul><li>Internal, often mineralized, connective tissue </li></ul></ul><ul><ul><li>Muscles on the outside </li></ul></ul><ul><ul><li>Cartilage – elasmobranchs </li></ul></ul><ul><ul><li>Other vertebrates – cartilage replaced by bone as embryo matures and develops </li></ul></ul>
  8. 8. Appendicular and axial skeleton <ul><li>Axial skeleton (80 bones) </li></ul><ul><ul><li>axis of the body </li></ul></ul><ul><ul><li>support and protection of main organs </li></ul></ul><ul><ul><ul><li>Skull </li></ul></ul></ul><ul><ul><ul><li>Sternum </li></ul></ul></ul><ul><ul><ul><li>Ribs </li></ul></ul></ul><ul><ul><ul><li>Vertebral Column + sacrum and coccyx </li></ul></ul></ul><ul><li>Appendicular skeleton (126 bones) </li></ul><ul><ul><li>anchors appendages to the axial skeleton </li></ul></ul><ul><ul><ul><li>Upper Extremities </li></ul></ul></ul><ul><ul><ul><li>Lower Extremities </li></ul></ul></ul><ul><ul><ul><li>Pectoral Girdle </li></ul></ul></ul><ul><ul><ul><li>Pelvic Girdle </li></ul></ul></ul>
  9. 9. Types of bones <ul><li>Long bones </li></ul><ul><ul><li>Long shaft (diaphysis) </li></ul></ul><ul><ul><li>Two joint surfaces (epiphyses) </li></ul></ul><ul><ul><li>Mostly compact bone </li></ul></ul><ul><ul><li>e.g. femur, tibia, fibula, radius, ulna </li></ul></ul><ul><li>Short bones </li></ul><ul><ul><li>Cube-shaped, mostly spongy bone </li></ul></ul><ul><ul><li>e.g. bones of wrist and ankle, patella </li></ul></ul><ul><li>Flat bones </li></ul><ul><ul><li>Thin and curved </li></ul></ul><ul><ul><li>e.g. skull and sternum </li></ul></ul><ul><li>Irregular bones </li></ul><ul><ul><li>Irregular and complicated shapes </li></ul></ul><ul><ul><li>e.g. spine and hips </li></ul></ul>
  10. 10. Joints or articulations <ul><li>Meeting of two bones </li></ul><ul><li>Types of joints </li></ul><ul><ul><li>Immovable </li></ul></ul><ul><ul><li>Slightly movable </li></ul></ul><ul><ul><li>Freely movable </li></ul></ul>
  11. 11. Bone Tissue <ul><li>Compact bone </li></ul><ul><ul><li>series of Haversian canals </li></ul></ul><ul><ul><li>concentric layers of bone cells (osteocytes) </li></ul></ul><ul><ul><li>new bone formed by osteocytes </li></ul></ul><ul><li>Spongy bone </li></ul><ul><ul><li>ends of long bones </li></ul></ul><ul><ul><li>less dense </li></ul></ul><ul><ul><li>contains red or yellow marrow </li></ul></ul><ul><li>Periosteum </li></ul><ul><ul><li>outer layer of bone </li></ul></ul><ul><ul><li>rich in nerve endings, blood, and lymphatic vessels </li></ul></ul><ul><ul><li>inner portion forms new bone or remodels existing bone </li></ul></ul>
  12. 12. Types of bone cells <ul><li>Osteoblasts </li></ul><ul><ul><li>immature bone cells </li></ul></ul><ul><ul><li>manufacture hormones and enzymes that aid in bone mineralization </li></ul></ul><ul><li>Osteocytes </li></ul><ul><ul><li>mature osteoblasts in lacunae (spaces) </li></ul></ul><ul><ul><li>form bone, maintain matrix </li></ul></ul><ul><ul><li>act for calcium homeostasis </li></ul></ul><ul><li>Osteoclasts </li></ul><ul><ul><li>responsible for bone reabsorption and shaping </li></ul></ul><ul><ul><li>located on bone surfaces </li></ul></ul>
  13. 13. Bone formation <ul><li>Intramembranous ossification  formation of the flat bones of the skull </li></ul><ul><li>Endochondral ossification  formation of long bones </li></ul>
  14. 14. Bone remodeling <ul><li>Resorption of bone (by osteoclasts) followed by replacement of bones (by osteocytes) </li></ul><ul><li>Functions to regulate calcium levels, repair damaged bones, and shape and sculpt the skeleton during growth </li></ul><ul><li>Rate is regulated by parathyroid hormones (PTH) and Vitamin D </li></ul>
  15. 15. Disorders of the skeletal system <ul><li>Osteoporosis </li></ul><ul><ul><li>Reduced bone density leading to fractures </li></ul></ul><ul><li>Rickets and osteomalacia </li></ul><ul><ul><li>Softening of bones leading to deformations and fractures </li></ul></ul><ul><li>Arthritis </li></ul><ul><ul><li>Inflammation of joints </li></ul></ul><ul><li>Bone fractures </li></ul><ul><li>Scoliosis, kyphosis </li></ul>

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